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Commit eca4549f authored by Zhang Yanfei's avatar Zhang Yanfei Committed by Greg Kroah-Hartman
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sysfs: Add crash_notes_size to export percpu note size 



For percpu notes, we are exporting only address and not size. So
the userspace tool kexec-tools is putting an upper limit of 1024
and putting the value in p_memsz and p_filesz fields. So the patch
add the new sysfile crash_notes_size to export the exact percpu
note size and let the kexec-tools parse it intead of using 1024.

The idea came from Vivek Goyal. And a later patch will be sent to
kexec-tools to let it parse the size.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: default avatarSimon Horman <horms@verge.net.au>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6ae07f27

drivers/base/cpu.c

+14 −0
Original line number Diff line number Diff line
@@ -132,6 +132,17 @@ static ssize_t show_crash_notes(struct device *dev, struct device_attribute *att 
	return rc;

}

static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);



static ssize_t show_crash_notes_size(struct device *dev,

				     struct device_attribute *attr,

				     char *buf)

{

	ssize_t rc;



	rc = sprintf(buf, "%lu\n", sizeof(note_buf_t));

	return rc;

}

static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);

#endif



/*
@@ -259,6 +270,9 @@ int __cpuinit register_cpu(struct cpu *cpu, int num) 
#ifdef CONFIG_KEXEC

	if (!error)

		error = device_create_file(&cpu->dev, &dev_attr_crash_notes);

	if (!error)

		error = device_create_file(&cpu->dev,

					   &dev_attr_crash_notes_size);

#endif

	return error;

}